The present invention relates to a process for preparing silicon carbide whiskers and, more particularly, to a process for preparing silicon carbide whiskers of a high quality with a high yield.
Since each whisker, constituting a single crystal of silicon carbide, exhibits excellent properties such as specific strength, specific elastic modulus, heat resistance, chemical stability and so on, the whiskers has a potential for use as a composite reinforcing material for metals, plastics and ceramics. The production of silicon carbide may be largely controlled by various factors such as the raw materials used, i.e., siliceous and carbonaceous materials, a ratio of composition, and an atmosphere and temperature of the reaction. The combination of these factors is significant in the production of silicon carbide whiskers of high quality with a high yield.
Heretofore, various techniques of preparing silicon carbide have been known: a process in which a silicon halide such as silicon tetrachloride is reacted with a carbonaceous source such as carbon tetrachloride, benzene or methane in hydrogen streams at high temperatures; a process utilizing a vapor raw material system in which, for example, a silane compound such as trichlorosilane (CH.sub.3 SiCl.sub.3) is pyrolyzed in hydrogen streams; and a process utilizing a solid raw material system in which, for example, a siliceous material such as silica sand or metal silicon is reacted with a carbonaceous material such as coke or graphite powder.